Change-speed and reversing gearing.



J. D. ABBOTT. CHANGE SPEED AND BEVBRSING GEARING.

APPLICATION FILED MAR. 15, 1910. V

Patented Oct. 11, 1910.

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JOHN DIXON ABBOTT, OF EASTBOURNE, ENGLAND.

CHANGE-SPEED AND REJERSING GEARING.

Specification of Letters Patent.

Application med March 15, 1910.

Patented Oct. 11, 1910.

serial No. 549,502,

To all whom it may concern.'

Be it known that I, JOHN DIXON ABBOTT, a subject of the King of Great Britain and Ireland, and a resident of Eastbourne, England, have invented certain new and useful Improvements in Change-Speed and Reversing Gearing; and I do hereby declare the following to be a full, clear, and exact description of the same.

This invention relates to improvements in change-speed and reversing gearing especially suitable for motortrams, and also suitable for motor-cars and other purposes.

The invention has for its objects, niet alia, to provide a change-speed and reversing gearing having two forward and two backward speeds, whereby the gearing will be particularly suitable for motor-trams and will dispense with the use of turntables, and to provide such a gear which is simpler and less costly to manufacture than existing gears of the kind and dispenses with the use of bevel wheels and offers a minimum of frictional resistance, and to provide such a gear which is compact in form and is adaptn ed to be contained in one easing.

lThe invention is illustrated on the accompanying drawings, in which Figure l is a plan-view showing the driving shaft displaced from its customary rela tion to the sprocket and countershafts to render the representation clearer. Fig. 2 is a diagrammatical. end view showing the proper relative positions of the three shafts.

According to the invention the sprocket or other shaft, 1, to be driven has loosely mounted on it two big wheels, B, G, which one at a time, are madev fast to the sprocket shaft, l, by an intervening sliding dog or equivalent clutch, 2, fast on the sprocket shaft, l, and adapted to engage either whe-el, B, G, at a time, or in other suitable manner. One of the big wheels, namely, B, is made fast to a small wheel, E, also loose on the sprocket shaft, l.

Fast on a countershaft, 3, which is arranged parallel to the sprocket shaft, l, are a big wheel, C, a small wheel, D, and a smaller wheel. or pinion, F. The small Wheel, D, is in constant mesh with the small wheel, E; and the wheel or pinion, F, is in constantmesh with the wheel, G.

On the driving or engine shaft, 4l, which is ,parallel to the sprocket-shaft, l, and the countershaft, 3, the three shafts being in triangular relation in end view, is a small driving wheel or pinion, A which is mounted so as to rotate with the driving shaft and is adapted to slide between the big wheel, B, on the sprocket shaft, l, and the big wheel, C, on the countershaft, 3, and to mesh with so as to directly drive either at a time.

To obtain the same forward and backward high speeds, and the same forward and backward slow speeds, the wheels, B, C, are made of the same diameter, and the small wheels, E, D, are made of the same diameter. The small wheels, E, D, merely act as intermediary wheels.

The desired reduction in the ratio of the high and low speeds is obtained by the ratio of the small wheel or pinion, F, to the big wheel, G. A convenient size for these wheels for a gear suitable for a motor-tram, is to make the big wheel, G, the same size as the big wheels, B, C, and to make the small wheel or pinion, F, about one-third of the diameter of the big wheel, G.

Any convenient means may be employed for sliding the clutch on the sprocket shaft, l, and the pinion, A, on the engine or driving shaft, 4E, and the whole gearing may be conveniently inclosed in one casing.

The operation of the gear is as follows (l) Forward high speed is obtained from driving pinion, A, through big wheel, B, and clutch, 2, to sprocket shaft, l. (2) Forward slow speed is obtained from driving' pinion, A, through big wheel, B, and small wheel, E, to small wheel, D, through countershaft, 3, and small wheel or pinion, F, to big wheel, G, through clutch, 2, to sprocket shaft, l. Backward-speed is obtained from driving pinion, A,`througl'1 big wheel, C, and countershaft, 3, to small wheel, D, through small wheel, E, and clutch, 2, to sprocket shaft, l. (il) Backward slow speed is obtained from driving pinion, A, through big wheel, C, and countershaft, 3, to small wheel or pinion, F, through big wheel, G, and clutch, 2, to sprocket shaft, l, It will thus be seen that the same train of second speed wheels, F, G, serves for both the forward first speed wheel, B, and the backward first speed wheel, C.

The invention is of advantage in that the arrangement comprises a minimum number of shafts and in that high speed in both directions, on which most work is done, is obtained through one and two pairs of gears only respectively. Besides, friction is reduced to a minimum as, including the on said shafts respectively, clutch mechal5 msm for connecting the Wheels on the driven shaft to the lat-ter, a driving shaft, and a slidable driving pinion mounted on the latter and adapted to mesh with either of said irst-speed wheels, suhstantiallv as described. d

In testimony whereof I aix my signature in presence of two subscribing witnesses.

vJOHN DIXON ABBOTT.

Witnesses HARRY JOHN MABEH, THOMAS FREDERICK NICHOLSON. 

